JP3219377B2 - Reflective liquid crystal display - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reflective liquid crystal display device which is bright, has high contrast, and has a wide viewing angle.

[0002]

2. Description of the Related Art Liquid crystal display elements have characteristics of being lightweight and thin, and thus are widely used in various applications including displays for portable information terminals. A liquid crystal display element performs display by changing the transmission intensity of light by driving liquid crystal molecules with an effective voltage of several volts, but the liquid crystal itself is a non-luminous substance and requires some other light source, and Light power for the light source that is much larger than the drive power is required. However, by using a reflection type liquid crystal display element provided with a reflector below the liquid crystal display element to display the image using ambient light, it is possible to realize a display element with extremely low power consumption and utilizing the inherent characteristics of liquid crystal.

In addition, the reflection type liquid crystal display element has a problem that brightness is obtained only in a regular reflection direction of light incident on the display element, because display is performed using ambient light. Therefore, in order to widen the viewing angle, a configuration using a scattering film that diffuses light to a region outside the specular reflection direction has been proposed.

As a conventional reflection type liquid crystal display device, for example, a device using a forward scattering film described in JP-A-8-201802 (hereinafter referred to as prior art I), and a device disclosed in JP-A-8-338993. A device using a scattering film also having a backscattering property described in a gazette (hereinafter, referred to as conventional technology II) is known.

FIG. 8 shows the structure of a reflection type liquid crystal display device as in the prior art I. Reference numeral 80 denotes a forward scattering film, 81 denotes a polarizing plate, 82 denotes a birefringent film, 83 denotes a liquid crystal cell,
84 is a transparent substrate, 85 is a color filter, 86 is a transparent electrode, 87 is a liquid crystal layer, 88 is a specular reflector, and 89 is a lower substrate.

[0006]

However, in the case of a configuration using a scattering film having a backscattering characteristic as in the above-mentioned prior art II, backscattering occurs when ambient light is incident on the liquid crystal display element. Therefore, there is a problem that the reflectivity in black display does not become sufficiently low, so that high contrast cannot be obtained.

In addition to the structure using a scattering film which also has backscattering, the structure using a dominant scattering film which has almost no backscattering characteristics and only strong forward scattering characteristics as in the prior art I described above. Also, when the scattering angle region is omnidirectional, light is diffused to a direction out of the field of view of the observer out of the light emitted from the liquid crystal cell due to the diffusion of light at the scattering film. In that case, since the emitted light is not effectively used, the reflectance in a direction within the field of view of the observer is reduced, and sufficient brightness is not obtained in white display, and the contrast is reduced. There is.

Accordingly, the present invention is directed to solving the above-mentioned problems in the prior art, and is characterized in that white display is bright, black display is sufficiently dark, high contrast can be obtained, and viewing angle dependency is small. It is a main object of the present invention to provide a reflective liquid crystal display device having the same.

A scattering film layer formed by laminating a polarizer, zero or one or more birefringent films, and a plurality of forward scattering films having almost no back scattering characteristics and strong forward scattering characteristics. And a reflective liquid crystal display device comprising a liquid crystal cell having a specular reflector,
At least one of the forward scattering films forming the scattering film layer is characterized in that the scattering angle range is asymmetric with respect to the normal direction of the film. By including at least one asymmetrical forward scattering film, its scattering characteristics are different at the time of entering and exiting the reflective liquid crystal display element, and the light is diffused in a specific direction, thereby collecting reflected light toward the observer. It has the effect of increasing the light properties and increasing the reflectance,
As a result, a black display with a sufficiently low reflectance and a white display with a sufficiently high reflectance are obtained, and the function and action of high contrast can be realized in the reflective liquid crystal display device.

[0010]

SUMMARY OF THE INVENTION The present invention provides a polarizer,
A liquid crystal cell having a birefringent film or a plurality of birefringent films, a scattering film layer formed by laminating a plurality of forward scattering films having little backscattering characteristics and strong forward scattering characteristics, and a specular reflector. In the reflection type liquid crystal display device, the forward scattering film which forms the scattering film layer is characterized in that each scattering angle range is asymmetric with respect to the normal direction of each film. As described above, all the forward scattering films have a scattering angle range that is asymmetric, and therefore, the light is diffused only in a specific direction because of different scattering characteristics when entering or exiting the reflective liquid crystal display element. This has the effect of increasing the light collecting property of the reflected light to the observer side and increasing the reflectivity, so that black display with sufficiently low reflectivity and white display with high reflectivity can be obtained. Thus, the function and operation of high contrast can be realized in the reflective liquid crystal display device.

Further, in addition to the above, the present invention further provides that all of the forward scattering films forming the scattering film layer have a projection direction on each film surface in a central angle direction of each scattering angle range. From 90 degrees counterclockwise with the azimuth angle of 0 degrees for the overall observer direction of the liquid crystal display device
It can be configured as a feature that falls within the range of up to 270 degrees. With such a configuration, the above-described object can be effectively achieved, and a corresponding specific operation and effect can be achieved.

Similarly, in the present invention, the projection directions of the center angle directions of the respective scattering angle ranges of the two forward scattering films of the forward scattering films forming the scattering film layer to the respective film surfaces are mutually different. 0 to 120
Or two of the forward scattering films forming the scattering film layer are projected on each film surface in the direction of the central angle of the respective scattering angle range. As one characterized by directions orthogonal to each other, or two of the forward scattering films forming the scattering film layer, the projection direction to each film surface in the central angle direction of each scattering angle range, Assuming that the overall viewing direction of the liquid crystal display element is an azimuth angle of 0 degree, and is approximately 135 degrees and 225 degrees counterclockwise, respectively, or similarly, two of the forward scattering films are respectively The projection direction to each film surface in the central angle direction of the scattering angle range of the is characterized by making an angle of approximately 180 degrees to each other,
Or also at least one of the forward scattering films
Each sheet is characterized in that the projection direction of the central angle direction of the scattering angle range on the film surface is approximately 180 degrees, with the azimuth angle of 0 degree as the overall viewing direction of the liquid crystal display element. It is also possible to achieve the above object effectively by each of these configurations,
Each of them can exert a specific effect.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In order to obtain a better understanding of the technical contents of the present invention, in particular, the problems to be solved and the means for solving the problems, a typical example of the present invention will be described with reference to FIGS. Embodiments and Reference Examples will be described.

(Reference Example) First, an embodiment and a reference will be described with reference to a cross-sectional view of the reflection type liquid crystal display device of FIG. 1 and a conceptual diagram showing the scattering angle direction of the forward scattering film of FIGS. 2 (a) and 2 (b). An example will be described.

FIG. 1 is a sectional view of a reflective liquid crystal display device according to an embodiment of the present invention and a reference example.
In FIG. 1, 10a is a forward scattering film (layer) whose scattering angle range is asymmetric with respect to the normal direction of the film, and 10b is a forward scattering film (layer) whose scattering angle range is symmetric with respect to the normal direction of the film. , 11 is a polarizer, 12 is a birefringent film layer, 13 is a liquid crystal cell, 14 is an upper transparent substrate, 15 is a color filter, 16 is a transparent electrode, 17 is a liquid crystal layer, 18 is a specular reflector, 19
Indicates a lower substrate.

FIG. 2A is a conceptual diagram showing a scattering angle direction when one forward scattering film is viewed from the side. 20 is a forward scattering film, 21 is a scattering angle range indicating a range of an incident angle of light scattered in the film among light incident on the forward scattering film, 22 is a central angle direction indicating a central angle of the scattering angle range, 23 is The direction of projection on the scattering film surface in the direction of the central angle, and 24 indicates forward scattered light.

FIG. 2B is a conceptual diagram showing the scattering angle direction of the forward scattering film when the reflective liquid crystal display device using one forward scattering film is viewed from above. Reference numeral 23 denotes a projection direction of the scattering angle range of the forward scattering film on the film surface in the central angle direction, 25 denotes a reflection type liquid crystal display element, 26 denotes an observer, and 27 denotes an azimuth angle φ.

Referring again to FIG. 1, a reference example will be described. Using a glass substrate as the upper transparent substrate 14 and the lower substrate 19,
On the upper transparent substrate 14, a color filter 15 having a pigment dispersion type of red, green, and blue stripe arrangement is formed by photolithography as a color filter 15, and a transparent electrode 16 is formed of indium, tin, oxide (ITO) pixels. An electrode was formed. On the lower substrate 19, a specular reflector 18 was formed by evaporating silver to form a metal reflective electrode.

A 5 wt% solution of N-methyl-2-pyrrolidinone of polyimide is printed on the transparent electrode 16 and the specular reflection plate 18, and cured at 200 ° C., and then a rayon cloth is applied so that the rubbing is antiparallel to each other. An alignment film was formed by performing an alignment treatment by a rotary rubbing method using a.

A thermosetting sealing resin containing 1.0 wt% of 5.7 μm diameter glass fiber is printed on a peripheral portion of the upper transparent substrate 14, and a 4.5 μm diameter resin bead is formed on the lower substrate 19. Spray 200 pieces / mm ² at upper transparent substrate
14 and the lower substrate 19 were bonded to the upper surface of the color filter 15 and the lower surface of the specular reflection plate 18, respectively, and the sealing resin was cured at a temperature of 150 ° C. Thereafter, an ester-based nematic liquid crystal having Δn = 0.14 was vacuum-injected, sealed with an ultraviolet curable resin, and then cured by irradiation with ultraviolet light.

On the upper transparent substrate 14 of the liquid crystal cell 13 thus formed, as a forward scattering film 10a having a scattering angle range asymmetric with respect to the normal direction of the film, Sumitomo Chemical Co., Ltd.
A forward scattering film (trade name: Lumisty) manufactured by Co., Ltd., with a scattering angle range 21 of 0 to 50 degrees measured from the film normal, the center angle direction 22 of the scattering angle range 21, that is, a film surface in the direction of 25 degrees. The projection direction 23 to the direction opposite to the observer 26 direction of the reflection type liquid crystal display element 25, that is, the azimuth angle 27 is φ = 180
We stuck so that it might be. A birefringent film layer 12 having a retardation value of 490 nm is bonded thereon so that the slow axis is orthogonal to the rubbing direction of the upper transparent substrate 14, and a neutral gray polarizer (Sumitomo) is further provided thereon as the polarizer 11. SQ1852AP (manufactured by Chemical Industry Co., Ltd.) was bonded so that its absorption axis was at an angle of 45 degrees with the rubbing direction of the upper transparent substrate 14. On top of this, a forward scattering film 10 whose scattering angle range is symmetric with respect to the film normal direction.
As b, those having a scattering angle range of −15 ° to 15 ° were bonded so that the scattering angle range was within the plane of φ = 90 ° and φ = 270 ° in the azimuth angle 27.

As described above, a normally black mode reflection type color liquid crystal display element which provides black display when no voltage is applied was obtained. In this liquid crystal display element, since the scattering angle range is provided with a forward scattering film that is asymmetric with respect to the normal direction of the scattering film, the light emitted from the display element is diffused only in a specific direction. It can be used effectively and has contrast in frontal characteristics 6.
4. A reflectance of 12.7% in terms of Y value in white display was obtained.

In the above-mentioned reference example, the liquid crystal cell is not limited to this mode, and a single polarizing film such as a simple matrix drive or an active drive by a thin film transistor (TFT) is used. As long as the liquid crystal cell can be displayed in a reflection type, substantially the same effect can be obtained by using the liquid crystal cell.

Although a metal reflective electrode containing silver as a component is used as the mirror reflector, the same effect can be obtained by using a metal reflective electrode containing aluminum as a component, for example.

The forward scattering film having a scattering angle range of 0 to 50 degrees or -15 to 15 degrees was used. For example, a film having a scattering angle range of 10 to 60 degrees was used. Can obtain the same effect. Although two forward scattering films are used here, a similar effect can be obtained with a configuration of three or more sheets.

In the above-mentioned reference example, the position of the forward scattering film in the reflection type liquid crystal display device is set as shown in FIG. 1. For example, the forward scattering film 10b having a symmetric scattering angle range.
However, even if the liquid crystal cell 13 is located between the liquid crystal cell 13 and the forward scattering film 10a whose scattering angle range is asymmetric, the same effect is still obtained.

(Embodiment 1) In Embodiment 1 of the present invention, FIG. 3 is a sectional view showing a basic structure of a reflection type liquid crystal display element, and FIG. 2 is a view conceptually showing a scattering angle direction of a forward scattering film. This will be described with reference to FIG.

In FIG. 3, reference numeral 30 denotes a forward scattering film layer whose scattering angle range is asymmetric with respect to the normal direction of the film, 31 denotes a polarizer, 32 denotes a birefringent film layer, 33 denotes a liquid crystal cell, and 34 denotes an upper transparent. A substrate, 35 is a color filter, 36 is a transparent electrode, 37 is a liquid crystal layer, 38 is a specular reflector, and 39 is a lower substrate.

The structure and manufacturing method of the liquid crystal cell of the present embodiment are the same as those of the above-mentioned reference example. On the upper transparent substrate 34 of the liquid crystal cell 33, as a forward scattering film layer 30 whose scattering angle range is asymmetric with respect to the normal direction of the film, a forward scattering film (trade name: Lumisty) manufactured by Sumitomo Chemical Co., Ltd. When the scattering angle range 21 is 0 to 50 degrees measured from the film normal, the central angle direction 22 of the scattering angle range 21
In other words, the projection direction 23 on the film surface in the direction of 25 degrees is opposite to the direction of the observer 26 of the reflective liquid crystal display element 25, that is, the azimuth angle.
27 is φ = 180 degrees, and the scattering angle range is from 10 degrees to 60 degrees
The films were bonded so that the projection direction 23 on the film surface in the central angle direction 22, that is, the 35-degree direction was φ = 90 degrees. Then, a birefringent film layer 32 having a retardation value of 490 nm is stuck thereon so that the slow axis is orthogonal to the rubbing direction of the upper transparent substrate 34, and a neutral gray polarizer is further formed thereon as the polarizer 31. (SQ1852AP, manufactured by Sumitomo Chemical Co., Ltd.) and subjected to an anti-glare (AG) treatment and an anti-reflection treatment were bonded so that the absorption axis was at an angle of 45 degrees with the rubbing direction of the upper transparent substrate 34.

In the reflection type liquid crystal display device of this embodiment configured as described above, the forward scattering film whose scattering angle range is asymmetric with respect to the normal direction of the scattering film is provided. The light emitted from the reflective liquid crystal display element is diffused only in a specific direction, the ambient light can be used very effectively, the contrast is 13.7 in the front characteristics, and the reflectance in white display is 12.80 in terms of Y value. %was gotten.

The liquid crystal cell 33 in this embodiment is
However, the present invention is not limited to only this mode, but may be a simple matrix drive or a thin film transistor (TF).
A liquid crystal cell that can be displayed in a reflection type using a single polarizing film, such as one that is actively driven in T), is sufficient. Even with such a configuration, substantially the same effect can be obtained. Can be.

Although a metal reflective electrode containing silver as a component is used as the specular reflector here, the present invention is not limited to this in view of the basic concept of the present invention. For example, aluminum is used as a component. Substantially the same effect can be obtained by using a metal reflective electrode or the like.

As the forward scattering film, one having a scattering angle range of 0 to 50 degrees and one having a scattering angle range of 10 to 60 degrees were used. However, the embodiment of the basic idea of the present invention is not limited thereto. Instead, the same effect can be obtained by using, for example, one having a scattering angle range of 0 to 30 degrees. Although two forward scattering films are used here, substantially the same effect can be obtained with a configuration of three or more films.

In the present embodiment, the forward scattering film layer
Although the position of 30 was set as shown in FIG. 3, it is not necessary that the position be 30 in order to embody the basic idea of the present invention. For example, a forward scattering film layer having a symmetric scattering angle range is used. 30 is a polarizer 31 and a birefringent film layer
Even if it comes between 32, the same effect can be obtained.

Embodiment 2 A reflection type liquid crystal display device according to Embodiment 2 of the present invention will be described.
Since the structure and manufacturing method are the same as those in the reference example and the first embodiment, the cross-sectional views of the reflection type liquid crystal display device shown in FIGS. 1 and 3 and the forward scattering shown in FIGS. This will be described with reference to a conceptual diagram showing the scattering angle direction of the film and FIG.

FIG. 4 shows a top view of a scattering film layer of a reflection type liquid crystal display device using three forward scattering films in which the scattering angle range in this second embodiment is asymmetric with respect to the normal direction of the film. It is a conceptual diagram which shows the scattering angle direction. In FIG. 4, reference numeral 40 denotes a reflective liquid crystal display device;
Reference numerals 42 and 43 denote projection directions on the film surface in the central angle direction of the scattering angle range of the forward scattering film, and 44 denotes an observer.

In this embodiment, the forward scattering film layer 10a whose scattering angle range is asymmetric with respect to the normal direction of the film.
(FIG. 1) and three forward scattering films (trade name: Lumisty) manufactured by Sumitomo Chemical Co., Ltd. were used as the forward scattering film layer 30 (FIG. 3), and one of them had a scattering angle range 21 (FIG. 2). Measured from 0 to 50 degrees measured from the film normal, the central angle direction of the scattering angle range, that is, the projection direction on the film surface in the 25-degree direction is 41, and the remaining two sheets have the scattering angle range 21. Measured from 10 degrees to 60 degrees measured from the film normal, the central angle direction of the scattering angle range, that is, the projection direction to the film surface in the 35-degree direction is 42 and 43, respectively, was laminated in layers. .

Further, as shown in FIG. 1, in the configuration including the forward scattering film 10b whose scattering angle range is symmetric with respect to the film normal direction, the scattering angle range is azimuth angle 27φ = 90 ° to φ.
= 270 degrees.

In the reflection type liquid crystal display device according to this embodiment having the above-described configuration, good black and white display can be achieved by effectively utilizing the ambient light, and not only high contrast can be realized but also reflection can be achieved. Since light was not scattered when the light was emitted from the liquid crystal display device in the user direction, it was confirmed that image blurring was slight.

In this embodiment, three or four forward scattering films are used. However, the embodiment of the present invention is not limited to this. Can be obtained substantially the same effect.

The liquid crystal cell is not limited to this mode, but may be a simple matrix drive,
A similar effect can be obtained with the configuration used here, as long as the liquid crystal cell can be displayed in a reflection type using a single polarizing film, such as a liquid crystal cell that is actively driven by a thin film transistor (TFT).

Although a metal reflective electrode containing silver as a constituent element is used as a mirror reflector, the present invention is not limited to this. For example, a metal reflective electrode containing aluminum as a constituent element can provide substantially the same effect. Can be obtained.

Although the forward scattering film having a scattering angle range of 0 to 50 degrees and 10 to 60 degrees was used, the embodiment of the basic principle of the present invention is not limited thereto. For example, the same effect can be obtained even if a scattering angle range of 0 to 30 degrees is used.

Further, in this embodiment, the position of the forward scattering film occupied by the structure of the reflection type liquid crystal display device of the forward scattering film is the position shown in FIGS. 1 and 3, but the basic principle of the present invention is embodied. Is not limited to this position. That is, for example, even if a forward scattering film having a symmetric scattering angle range is provided between the polarizing plate and the birefringent film layer, the effect obtained is substantially the same.

Embodiment 3 A reflection type liquid crystal display device according to Embodiment 3 of the present invention will be described.
Since the structure and fabrication are the same as those of the reference example and the first embodiment, the cross-sectional view of the reflection type liquid crystal display device of FIGS. 1 and 3 and the scattering angle of the forward scattering film of FIGS. This will be described with reference to a conceptual diagram showing directions and FIG.

FIG. 5 is a top view of a scattering film layer of a reflective liquid crystal display device using two forward scattering films in which the scattering angle range is asymmetric with respect to the normal direction of the film in the third embodiment of the present invention. It is a conceptual diagram which shows the scattering angle direction when it is. In FIG. 5, 50 is a reflective liquid crystal display element,
51 and 52 are projection directions on the film surface in the central angle direction of the scattering angle range of the forward scattering film, 53 are angles formed by the projection directions on the film surface in the central angle direction of the scattering angle range of the two films, and 54 is Each observer is shown.

In this embodiment, the forward scattering film layer 10a whose scattering angle range is asymmetric with respect to the normal direction of the film.
And as the forward scattering film layer 30, Sumitomo Chemical Co., Ltd.
Using two forward scattering films (trade name: Lumisty)
The scattering angle range 21 is from 0 to 50 degrees measured from the film normal, and the projection directions 51 and 52 on the film surface in the central angle direction of the scattering angle range, that is, the 25-degree direction are azimuth angles φ = 225 degrees, respectively. , Φ = 135 degrees.

Also, as shown in FIG. 1, in the configuration including the forward scattering film 10b whose scattering angle range is symmetric with respect to the film normal direction, the scattering angle range is such that the azimuth angle 27 is φ = 90 degrees and φ = 270 degrees. Laminated so as to be in the plane.

According to this embodiment configured as described above, by providing the forward scattering film whose scattering angle range is asymmetric with respect to the normal direction of the scattering film, the light emitted from the reflection type liquid crystal display device is provided. Is diffused only in a specific direction, so that ambient light can be used effectively. The contrast is 8.7 in frontal characteristics, and the reflectance in Y value conversion of white display is 1
2.29% were obtained. A contrast of 10.5 was also obtained in the left-right direction. With this configuration, good black-and-white display can be achieved in many directions, high contrast can be obtained, and natural viewing angle characteristics can be realized.

Also, when the angle 53 formed by the projection direction on the film surface in the central angle direction 22 of the scattering angle range 21 of the two forward scattering films forms an angle between 0 ° and 120 °,
It was confirmed that good black-and-white display was possible not only in one direction but also in many directions, and high contrast was obtained.
In particular, it was confirmed that good characteristics were obtained when the projection directions of the central angle directions of the scattering angle ranges of the two forward scattering films on the respective film surfaces were orthogonal to each other. Representative examples of this configuration are shown in FIGS.

When the angle 53 formed by the projection direction of the center angle direction 22 of the scattering angle range 21 of the two forward scattering films on the film surface is antiparallel, the scattering angle range 21 is measured from the film normal. The projection angles 51 and 52 on the film surface are azimuth angles φ = 0 degrees and φ =
Two sheets were stuck so as to be 180 degrees. 10 measured from the front
In terms of the characteristics from the degree, the contrast was 11.7 and the reflectivity of the white display was 13.30% in terms of the Y value in both the azimuth angles φ = 0 ° and 180 °. Not only the azimuth direction of the normal viewing angle,
It was confirmed that good black and white display was possible even in the opposite direction, and high contrast was obtained. Representative examples of this configuration are shown in FIGS.

In the case where the angle formed by the projection direction of the center angle direction 22 of the scattering angle range 21 of one of the plurality of forward scattering films onto the film surface is an azimuth angle φ = 180 degrees, In the case of parallel display, the reflectance of white display is 13.30% in terms of Y value conversion, while the scattering angle range 21 is from 0 degree to 5 degrees.
When the angle 53 formed by the projection direction on the film surface is 0 degrees, and the angles 53 are antiparallel with azimuth angles φ = 30 degrees and φ = 210 degrees, respectively, the reflectance in Y value conversion of white display is 12.78%. is there. That is, the characteristics in the azimuth angle φ = 0 degree direction are excellent by configuring the forward scattering film so that the projection direction on the film surface in the central angle direction 22 of the scattering angle range 21 of the forward scattering film is azimuth angle φ = 180 degrees. It was confirmed that it became.

In the embodiment of the present invention, the liquid crystal cell is not limited to this mode, and one liquid crystal cell, such as a simple matrix drive or an active drive by a thin film transistor (TFT), is used. A similar effect can be obtained with the configuration used here as long as the liquid crystal cell can be displayed in a reflection type using a film.

Although a metal reflective electrode containing silver as a constituent element is used as a specular reflector, this is not the only effective method for embodying the basic philosophy of the present invention and providing an intended effect. For example, substantially the same effect can be obtained by using a metal reflective electrode containing aluminum as a component.

Although the forward scattering film having a scattering angle range of 0 ° to 50 ° was used, the present invention is not limited to this in order to embody the basic idea of the present invention and bring about the desired effect. However, substantially the same effect can be obtained by using, for example, one having a scattering angle range of 10 degrees to 60 degrees. Although two or three forward scattering films are used here, the present invention is not limited to this, and a similar effect can be obtained with a configuration of three or more sheets.

Further, in this embodiment, the position of the forward scattering film in the reflection type liquid crystal display device is set to the position shown in FIGS. 1 and 3, but this position is inevitably used for embodying the basic principle of the present invention. However, the same effect can be obtained even if, for example, a forward scattering film having a symmetric scattering angle range is provided between the polarizing plate and the birefringent film layer.

[0057]

As described above, according to the present invention, by including a forward scattering film whose scattering angle range is asymmetric with respect to the normal direction of the film, it is possible to reduce the scattering angle range at the time of incidence on the reflection type liquid crystal display element or Since the scattering property at the time of emission can be made different, it can be diffused only in a specific direction, and the light collecting property of the reflected light to the user side is enhanced, the reflectance is increased, and a good white display is obtained. By using a forward scattering film having almost no back scattering characteristics, a black display with a sufficiently low reflectance can be obtained, and an effective effect of realizing high contrast in a reflection type liquid crystal display device can be obtained.

Further, by stacking forward scattering films in which the projection direction to the film surface in the direction of the central angle of the scattering angle range is varied, good black-and-white display can be achieved in many directions and high contrast can be obtained. Thus, a useful effect that natural viewing angle characteristics can be realized is brought about.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a reflective liquid crystal display device illustrating a reference example and a typical embodiment of the present invention.

2A is a conceptual diagram showing a scattering angle direction when one forward scattering film is viewed from the side; and FIG. 2B is a front view when a reflective liquid crystal display device using one forward scattering film is viewed from above. Conceptual diagram showing the scattering angle direction of the scattering film

FIG. 3 is a sectional view of a reflective liquid crystal display device according to the first embodiment of the present invention.

FIG. 4 is a conceptual diagram showing a scattering angle direction of a forward scattering film when a scattering film layer of a reflective liquid crystal display element according to a second embodiment of the present invention is viewed from above.

FIG. 5 is a conceptual diagram showing a scattering angle direction of a forward scattering film when a scattering film layer of a reflective liquid crystal display element according to a third embodiment of the present invention is viewed from above.

FIG. 6 is a diagram showing a scattering angle direction (from 0 ° to 120 °) of a forward scattering film when the scattering film layer of the reflective liquid crystal display element according to Embodiment 3 of the present invention is viewed from above.

FIG. 7 is a diagram showing a scattering angle direction (in the case of antiparallel) of a forward scattering film when a scattering film layer of a reflective liquid crystal display element according to Embodiment 3 of the present invention is viewed from above.

FIG. 8 is a cross-sectional view of a conventional reflective liquid crystal display device.

[Explanation of symbols]

10a Forward scattering film layer whose scattering angle range is asymmetric with respect to the normal direction of the film 10b Forward scattering film layer whose scattering angle range is symmetric with respect to the normal direction of the film 11 Polarizer 12 Birefringent film layer 13 Liquid crystal cell 14 Upper transparent substrate 15 Color filter 16 Transparent electrode 17 Liquid crystal layer 18 Mirror reflector 19 Lower substrate

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Ogawa Tetsudo 1006 Kazuma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) References JP-A 9-113893 (JP, A) JP-A 8- 112755 (JP, A) JP-A-8-87006 (JP, A) JP-A-10-154817 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G02F 1/1335 G09F 9 / 00-9/46

Claims (7)

(57) [Claims] 1. A scattering film layer formed by laminating a polarizer , one or more birefringent films, a plurality of forward scattering films having almost no back scattering characteristics and strong forward scattering characteristics, and a mirror surface In a reflection type liquid crystal display device comprising a liquid crystal cell having a reflection plate, all of the forward scattering film forming the scattering film layer ,
Wherein the scattering angle range is asymmetric with respect to the normal direction of each film. 2. The forward scattering forming said scattering film layer.
All of the film has a central angle in each scattering angle range
The direction of projection on each film surface in the
With the azimuth angle of 0 degrees for the overall observation direction of the child,
Claims that fall in the range from 90 degrees to 270 degrees
Item 2. A reflective liquid crystal display device according to item 1 . 3. Two of the forward scattering films forming the scattering film layer have a projection angle of 0 ° with respect to each film surface in a central angle direction of each scattering angle range .
Reflection type liquid crystal display device according to claim 1 or 2, wherein the forming an angle in the range of up al 120 degrees. 4. Two of the forward scattering films forming the scattering film layer, the projection directions of the central angle directions of the respective scattering angle ranges on the respective film surfaces are orthogonal to each other .
Reflection type liquid crystal display device according to claim 1 or 2, wherein the that. 5. Two of the forward scattering films forming the scattering film layer each have a liquid crystal display whose projection direction on each film surface in the center angle direction of each scattering angle range.
Counterclockwise rotation with the azimuth angle of 0 °
Rinisorezore approximately 135 degrees, the reflection type liquid crystal display device of claim 1 Symbol mounting characterized in that it is a 225 degrees. 6. Two of the forward scattering films forming the scattering film layer, the projection directions of the central angle directions of the respective scattering angle ranges on the respective film planes are substantially equal to each other.
Reflection type liquid crystal display device according to claim 1 or 2, wherein the angle of 0 degrees. One even without least of 7. front scattering films for forming said scattering film layer is projection direction of the central angle direction of the full Irumu surface of the scattering angle range of that, the liquid crystal
Approximately 180 with the azimuth angle of 0 °
According to claim 1, characterized in that those constituting a degree,
7. The reflective liquid crystal display device according to 3, 4 or 6 .